GB1405825A - Neutron detector - Google Patents

Abstract

1405825 Detecting neutrons SIEMENS AG 27 July 1973 [9 Aug 1972] 35983/73 Heading G6P A neutron detector comprises an emitter arrangement insulated from a surrounding collector so that, in use, neutron radiation falling on the emitter arrangement produces an output signal, the emitter arrangement comprising two materials which differ from each other as regards their relation between sensitivities to neutron radiation and gamma radiation. In one embodiment (Fig. 1, not shown) two emitters (2, 3) in the form of separate filaments are encased in a non-neutron responsive collector (1) of nickel alloy or stainless steel; one emitter (2) is made of γ-responsive material (e.g. a nickel alloy), while the other (3) is made of a material responsive to both neutron and γ radiation (and is preferably of the same atomic number as the material of the one emitter), e.g. cobalt or vanadium. In use, by connecting respective output leads (9, 8) to inputs of a differential amplifier, an indication of neutron flux independent of γ-flux is obtained. In another embodiment (Fig. 2, not shown) a composite rod emitter (15) comprises alternate sections (19, 20) of two different materials whose γ sensitivities, relative to the collector, are of opposite polarities, at least one of the materials also being neutron-responsive. Sections (19) of tantalum, zirconium or platinum may alternate with sections (20) of cobalt, or alternate sections may be of vanadium and rhodium respectively. In a further embodiment (Fig. 3, not shown), similar to the previous one, the emitter comprises two different materials provided in the form of respective wires (22, 23) twisted together. In a final embodiment (Fig. 5, not shown) the emitter (15) comprises a pulverulous mixture (28) of the two different materials contained within an insulating tube (25) closed by end-plugs (26, 27). The inner surface of the tube may be metallized for the purpose of making electrical connection with the emitter.